The purpose of this project is to test in vivo viability of red cells stored for 42 days after filtration to remove white cells. The filtration of red cells to remove both lymphocytes and neutrophils from the stored red cell is usually done at the bedside. The technology is to remove the white cells shortly after the unit is donated. It is hoped that by removing neutrophils and lymphocytes before storage there will be a reduced potential for alloimmunization of transfusion recipients.